JPH11225962A - Objective refracting power measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute the measurement corresponding to the condition of the eyes to be inspected by mounting a plurality of light receiving elements along the direction separating from the optical axis of the measurement light to be received, and selecting the light receiving element to be used in the measurement from a plurality of light receiving elements. SOLUTION: A light receiver 17 comprises four divided light receiving elements 50-53, and the light receiving elements 60a-c, 61a-c, 62a-c and 63a-c. The latter light receiving elements are mounted in such manner that a plurality of light receiving elements are mounted along the directions separating from the optical axis of the measurement light to be received by the light receiving elements. The result of the selection by a selector switch 70 which selects the light receiving element to be used in the measurement is input to a switching circuit 71 through a processer 77, and only an output signal from the selected light receiving element is output to a refracting power calculating circuit 72 through the switching circuit 71. The refracting power of the eyes to be inspected is calculated on the basis of the output signal from the selected input light receiving elements 60a-c, 61a-c, 62a-c, 63a-c in reference to the conversion table stored in a conversion table memory part 73, and output to a superimposing circuit 75.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective refractive power measuring apparatus for objectively measuring the refractive power of an eye to be examined.
In particular, the present invention relates to an objective refractive power measurement device capable of performing measurement according to the state of an eye to be examined.

[0002]

2. Description of the Related Art An objective eye refractive power measuring device for objectively measuring the refractive power of an eye to be examined is widely used today. Such an objective eye refractive power measuring apparatus is disclosed in JP-A-55-16053.
8 has been proposed by the present applicant.

In this objective eye refractive power measuring apparatus, a measuring light is projected on a fundus of an eye to be inspected, the measuring light reflected by the eye to be inspected is received by a light receiving element of a light receiver, and the received measuring light is measured. The refractive power of the subject's eye is calculated based on the phase. This objective eye refractive power measuring device was designed to measure on the assumption that the subject's eye is normal and that the pupil is dilated by a predetermined amount or more. It was designed in a constant shape.

[0004] Such a light receiver is shown in FIGS.
In FIGS. 13 to 15, a pair of upper and lower light receiving elements 101 and 102 and a pair of right and left light receiving elements 103 and
A measurement value is calculated based on the phase difference between the measurement light received by the light receiving elements 101 and 102 and the measurement light received by the light receiving elements 103 and 104. Reference numerals 105 to 108 denote four-divided light receiving elements for detecting the alignment state of the objective eye refractometer with respect to the eye to be examined.

In FIGS. 13 to 15, reference numeral E1 denotes a position corresponding to the inside of the iris of the eye to be inspected (that is, the pupil diameter of the eye to be inspected), reference numeral E2 denotes a position corresponding to the outside of the iris of the eye to be inspected, and reference numeral E3 denotes an object to be inspected. The ranges of the reflected light reflected by the cornea of the optometry are shown respectively (reference numerals E1 to E3 have the same meaning in other drawings). As shown in FIG. 13, when the measurement state satisfies the above premise, the light receiving elements 101 to 104 are completely inside the pupil diameter E1 and the range E3 of the reflected light is the light receiving element 101. As a result, it is possible to perform the measurement as designed, so that an accurate measurement value can be obtained.

[0006]

Here, the pupil of the eye to be examined may not be sufficiently mydriatic due to aging, illness, and the like. In such a case, the measurement light is blocked by the iris. The measurement light reaching the light receiving element is limited. However, the conventional objective eye refractive power measuring device is based on the premise that the measuring light has a predetermined width as described above, and the light receiving element is simply designed in a fixed shape, so that the measuring light is blocked by the iris. In such a case, the measurement light may not be received in a correct state. In addition, even when there is partial opacity in the lens, etc., the measurement light is blocked by the turbidity, so the range of the measurement light reaching the light receiving element is limited. There was a possibility that it could not be done.

For example, as shown in FIG. 14, the pupil diameter E1 is small, and the light receiving elements 102 and 103 are located inside the pupil diameter E1.
Are not completely settled, these light receiving elements 10
The signals output from the detectors 2 and 103 may be disturbed, and the phase difference may be measured to be smaller than the actual one, or the phase difference may fluctuate greatly due to a slight positional shift of the subject's eye, and the measurement may be inaccurate and unstable. Was.

Further, when the eye to be examined has an intraocular lens, the intraocular lens has a refractive power larger than that of the crystalline lens, or has a flat surface compared to the crystalline lens. More measurement light is reflected on the surface of the eye, this reflected light is mixed with the measurement light reflected on the fundus,
Again, there was a risk that accurate measurements could not be made. In particular, the foldable acrylic intraocular lens, which is often used recently, has a relatively small curvature due to its miniaturization, and has a large surface reflection in terms of the material, so that the measurement light on the lens surface is hardly affected. Reflection was a problem.

For example, as shown in FIG. 15, the range of reflected light E3 is expanded by reflection on the surface of the intraocular lens,
In some cases, the range E3 of the reflected light overlaps the light receiving elements 101 and 104. In such a case, the reflected light may be mixed with the measurement light reflected from the fundus of the eye to be inspected, and accurate measurement may not be performed.

The present invention has been made in view of the problems in such a conventional objective eye refractive power measuring apparatus, and adjusts the position of a light receiving element, the width of a measuring beam, and the like according to the state of the eye to be examined. It is an object of the present invention to provide an objective eye refractive power measuring device capable of forming an ideal light receiving state by performing the measurement and stabilizing the measurement and improving the measurement accuracy.

[0011]

In order to solve the above-mentioned problems in the conventional objective eye refractive power measuring apparatus, the present invention according to the first aspect of the present invention provides a projection apparatus for projecting measuring light onto the fundus of an eye to be examined. An optical system, a light receiving optical system for receiving, via a light receiving element, measurement light projected by the projection optical system and reflected by the eye to be inspected, and an eye to be inspected based on the measurement light received by the light receiving optical system. And a calculating means for calculating the refractive power of the objective type refractive power measuring device, wherein a plurality of light receiving elements of the light receiving optical system are arranged along a direction away from the optical axis of the measurement light received by the light receiving element, It is characterized by including a selecting means for selecting a light receiving element to be used for measurement from a plurality of light receiving elements.

[0012] The present invention described in claim 2 provides the present invention in claim 1.
According to the present invention, the calculating means calculates the refractive power of the eye to be inspected based on predetermined information of the light receiving element selected by the selecting means.

[0013] The present invention described in claim 3 provides the present invention.
In the present invention according to the second aspect, the display device further includes a display unit that displays the eye to be inspected, and the display unit is configured to display predetermined information for selecting the light receiving element in an overlapping manner on the eye to be inspected. ing.

The present invention described in claim 4 provides the present invention as defined in claim 1.
In the present invention described in any one of (3) to (3), the pupil detecting means for detecting the position and shape of the pupil of the eye to be inspected, and the position and shape of the light receiving element currently selected by the selecting means are detected by the pupil detecting means. Judgment means for judging whether or not it corresponds to the position and shape of the pupil, and if the judgment means judges that it does not correspond, the light-receiving element currently selected is detected by the pupil detection means. Switching means for switching to a light receiving element having a position and shape corresponding to the position and shape of the pupil.

According to a fifth aspect of the present invention, there is provided a projection optical system for projecting measurement light onto the fundus of an eye to be inspected, and a light receiving element for receiving the measurement light projected by the projection optical system and reflected by the eye to be inspected. A light receiving optical system that receives light through the optical system, and an objective refractive power measurement device that includes a calculating unit that calculates the refractive power of the eye to be examined based on the measurement light received by the light receiving optical system. Pupil detecting means for detecting a position and a shape; determining means for determining whether the position and the shape of the light receiving element correspond to the position and the shape of the pupil detected by the pupil detecting means; And information adding means for adding predetermined information indicating the reliability of the refractive power calculated by the calculating means based on the result of the determination.

According to a sixth aspect of the present invention, there is provided a projection optical system for projecting measurement light onto the fundus of an eye to be inspected, and a light receiving element for receiving the measurement light projected by the projection optical system and reflected by the eye to be inspected. A light receiving optical system that receives light through the light receiving optical system, and an objective refractive power measuring device including a calculating unit that calculates a refractive power of the subject's eye based on the measurement light received by the light receiving optical system. A plurality of diaphragms for narrowing the received measurement light to different ranges according to the measurement state, and an arbitrary diaphragm among the plurality of diaphragms is substantially conjugate with the subject's eye between the light receiving element and the subject's eye. Aperture switching means selectively disposed at a position.

The present invention according to claim 7 provides the present invention according to claim 6.
In the present invention, the calculation means calculates the refractive power of the eye to be inspected based on the stop arranged by the stop switching means.

According to the present invention, there is provided a projection optical system for projecting measurement light onto the fundus of an eye to be inspected, and a light receiving element for receiving the measurement light projected by the projection optical system and reflected by the eye to be inspected. A light receiving optical system that receives light through the optical receiving device, and an objective refractive power measuring device including a calculating unit that calculates the refractive power of the eye to be inspected based on the measurement light received by the light receiving optical system, wherein the light receiving element is A plurality of variable power lenses for changing the magnification of the measurement light so as to be completely covered with the measurement light, and any of the plurality of variable power lenses, between the light receiving element and the subject's eye. And a lens switching unit selectively disposed at a position substantially conjugate with the eye to be examined.

The present invention described in claim 9 provides the present invention according to claim 8.
In the present invention, the calculation means calculates the refractive power of the eye to be inspected based on the variable power lens arranged by the lens switching means.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of an objective eye refractive power measuring apparatus (hereinafter, simply referred to as the present apparatus) of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing the optical configuration of the present apparatus viewed from the side, FIG. 4 is a block diagram showing the electrical configuration of the present apparatus, FIG. 5 is a view taken along the line AA ′ of FIG.
FIG. 3 is a diagram showing a display screen of a TV monitor.

First, the configuration of the present apparatus will be described, and then the refractive power measuring operation by the present apparatus will be described. As shown in FIG. 1, the present apparatus includes a measurement optical system 1 for objectively measuring the refractive power of the eye E, a fixation optical system 2 for fixating the eye E in a predetermined direction, and And an observation optical system 3 for observing the eye E to be examined.

The measurement optical system 1 includes a projection optical system that projects measurement light onto the fundus of the eye E, and a measurement light that is projected by the projection optical system and reflected by the fundus of the eye E. And a light receiving optical system for receiving light. The projection optical system includes an infrared light source 11, a lens 12, a chopper 1
3 and a half mirror 14, the measuring light emitted from the infrared light source 11 is scanned by a chopper 13 via a lens 12, and the scanned measuring light is Project onto the fundus of E. The light receiving optical system includes a lens 15, a stop 16, and a light receiver 17. The measuring light reflected from the fundus of the eye E is stopped down to a predetermined range by the stop 16 via the lens 15, and is stopped down. The measured light is received by the light receiver 17. The features of the light receiver 17 will be described later.

The fixation optical system 2 guides the fixation light emitted from the visible light source 21 and transmitted through the fixation target 22 to the half mirror 24 via the lens 23, and receives the fixation light via the half mirror 24 and the half mirror 25. The image is projected onto the optometry E. In addition, the observation optical system 3 applies a total reflection mirror to the observation light projected by the infrared light source 31 provided on the front surface of the apparatus and reflected by the anterior segment of the eye E through the half mirrors 24 and 25 described above. The observation light reflected by the total reflection mirror 32 is guided to the lens 3.
The light is received by the CCD camera 34 via the third camera 3. This CCD
The observation light received by the camera 34 is displayed as an eye image on a TV monitor 76 described later.

Here, the light receiver 17 of the measuring optical system 1 will be described. As shown in FIG. 5A, the light receiver 17 includes four light receiving elements 50 to 53 and light receiving elements 60a to 60
0c, 61a to 61c, 62a to 62c, 63a to 63
c. In FIG. 5A, one of the directions in which the measurement light scans the eye E is shown as the Y direction, and the other is shown as the X direction. In the following description, “up and down” means the Y direction, and “left and right” means the X direction. It shall be shown respectively.

First, the four-divided light receiving elements 50 to 53 detect the alignment state of the present apparatus with respect to the eye to be inspected in the same manner as in the prior art. When the alignment state is proper, the optical axis of the measurement light reaching the light receiver 17 is adjusted. Center position (Fig. 5
(Indicated by a symbol P in (a)) are arranged at equal positions in the upper, lower, left and right directions. Then, whether or not the alignment state is proper is detected based on the difference in the amount of received light of the measurement light received by each of the four divided light receiving elements 50 to 53.

Next, the light receiving elements 60a-60c, 61a-
The configurations of 61c, 62a to 62c and 63a to 63c will be described. In the present embodiment, a plurality of light receiving elements are arranged along a direction away from the optical axis of the measurement light received by the light receiving elements. That is, in the related art, a total of four light receiving elements, a pair of upper and lower light receiving elements and a pair of left and right light receiving elements, are provided with respect to the center position P. Upper and lower three pairs of light receiving elements 6
A total of twelve light receiving elements are provided: 0a to 60c, 61a to 61c, and three pairs of left and right light receiving elements 62a to 62c, 63a to 63c.

More specifically, the light receiving element 60a and the light receiving element 61a, the light receiving element 60b and the light receiving element 61b,
0c and the light receiving element 61c are vertically symmetrically arranged with respect to the center position P, respectively, and form a vertical pair. The light receiving element 62a and the light receiving element 63a, the light receiving element 62b and the light receiving element 63b, and the light receiving element 62c The light receiving elements 63c are arranged substantially symmetrically with respect to the center position P and form a left and right pair.

Then, three pairs of light receiving elements 60a to 60c, 6
1a to 61c are arranged such that a plane including the direction of one measurement meridian, that is, the Y direction, and the optical axis of the measurement light received by the light receiving element passes through the center of each element, and three pairs of light receiving elements 62a 62c and 63a to 63c are arranged at positions where the plane including the direction of the other measurement meridian, that is, the X direction, and the optical axis of the measurement light received by the light receiving element passes through the center of each element.

These light receiving elements 60a-60c, 61a-
61c, 62a to 62c and 63a to 63c are configured separately from each other, and can independently receive measurement light and perform photoelectric conversion. And the light receiving element 60
a to 60c, 61a to 61c, 62a to 62c and 63
When the measurement light is received at a to 63c, each light receiving element 60
a to 60c, 61a to 61c, 62a to 62c and 63
Signals are output from a to 63c to a light receiving element switching circuit 71 described later. In addition, from the center position P, each light receiving element 60a-6
0c, 61a-61c, 62a-62c and 63a-6
The distance to 3c is not limited to the illustrated distance, and for example, the mutual interval between the light receiving elements 60a, 60b, and 60c may be any distance without being in close contact as illustrated. These distances and mutual intervals are appropriately determined based on empirical values or experimental values.

Next, the electrical configuration of the apparatus will be described with reference to FIG. In this apparatus, in addition to the above-described optical elements shown in FIG. 1, as shown in FIG.
0, light receiving element switching circuit 71, refractive power calculation circuit 72 serving as calculation means, conversion table storage section 73, element information presentation section 7
4. A superimpose circuit 75, a TV monitor 76 as a display means, and a microprocessor 77 are provided.

The light receiving element switching switch 70 and the light receiving element switching circuit 71 include light receiving elements 60a to 60c and 61a to 61
A selection means for selecting a light receiving element to be used for measurement among c, 62a to 62c and 63a to 63c. Specifically, the light receiving element changeover switch 70 includes a push button for selecting the light receiving element of the a system, a push button for selecting the light receiving element of the b system, and a push button for selecting the light receiving element of the c system. When the examiner presses all or any part of these three push buttons, the light receiving element to be used for measurement is specified. The light receiving elements of the a system are the light receiving elements 60a, 61a, 62a, 63a, the light receiving elements of the b system are the light receiving elements 60b, 61b, 62b, 63b, and the light receiving elements of the c system are the light receiving elements 60c, 61c, 62c, 6
3c, and so on.

The light receiving element switching circuit 71 includes a light receiving element 6
0a to 60c, 61a to 61c, 62a to 62c, 63
These are multiplexers disposed between a to 63c and the refractive power calculation circuit 72. The selection result of the light receiving element in the light receiving element switch 70 is input to the light receiving element switching circuit 71 through the microprocessor 77, and only the output signal from the selected light receiving element is output through the light receiving element switching circuit 71 to the refractive power calculation circuit. 72 is output. For example, when the push button for selecting the light receiving element of the system a of the light receiving element changeover switch 70 is pressed, the light receiving elements 60a, 61
Only the output signals from a, 62a and 63a are output to the refractive power calculation circuit 72.

The refractive power calculation circuit 72 is provided with a light receiving element 60a-60c, 61a-61c, 62a-6 inputted to itself.
2c, the refractive power of the subject's eye is calculated based on the output signals from 63a to 63c, and output to the superimpose circuit 75. The calculation of the refractive power is basically performed according to the same principle as that of the related art, but at the time of this calculation, the refractive power calculation circuit 72 refers to the conversion table stored in the conversion table storage unit 73. This conversion table shows a correspondence between the phase difference of the measurement light received by the light receiving element and the refractive power of the eye to be examined, and a conversion table showing the correspondence when the light receiving element of the a-system is selected. In addition to the conversion table indicating the correspondence when the light receiving element of the b-system is selected, the conversion table indicating the correspondence when the light-receiving element of the c-system is selected, for example, the light-receiving element of the a-system and the light-receiving element of the b-system The conversion table includes a conversion table indicating the correspondence when a plurality of light receiving elements are selected, as in the case where is selected.

The reason for using such a conversion table is as follows. That is, in FIG. 5A, as described above, the light receiving element of the system a, the light receiving element of the system b, and the light receiving element of the system c are arranged at different positions with respect to the center position P of the optical axis of the measurement light. . Here, in the case where the light receiving elements of the c-system, which are arranged close to the center position P of the optical axis, that is, 60c, 61c, 62c, and 63c, are used for measurement, the phase difference between the pupil parts close to each other is measured. Therefore, these light receiving elements 60c, 61c, 62c
And 63c have a small phase difference between the measurement lights received. On the other hand, the light receiving elements of the a system arranged at positions far from the center position P of the optical axis, that is, 60a, 61a, 6
When 2a and 63a are used for the measurement, the phase difference between the pupil parts separated from each other is measured, so that the phase difference of the measurement light received by these light receiving elements 60a, 61a, 62a and 63a is large. Become.

That is, while the refractive power of the eye to be examined is constant, the measured phase difference differs depending on the position of the light receiving element. Therefore, the correspondence between the phase difference and the refractive power of the eye to be examined is determined by the light receiving element. And the refractive power is calculated based on the correspondence. In the present embodiment, the refractive power is calculated by providing the conversion table as described above. However, instead of the conversion table, for example, the refractive power is calculated using a predetermined coefficient which is predetermined based on the position of the light receiving element. May be performed. Alternatively, the calculation may be performed using a predetermined calculation expression instead of the conversion table.
In the above description, the conversion table is provided to correct the phase difference based on the position of the light receiving element. However, when the shape is different not only in the position of the light receiving element, for example, the conversion table is located away from the center position P of the optical axis of the measurement light. In the case where the light receiving area of the light receiving element is increased in accordance with the above, a conversion table for correcting a phase difference based on the position and shape of the light receiving element is provided. That is, the refractive power of the subject's eye is calculated based on predetermined information on the position, shape, and the like of the selected light receiving element.

The refractive power calculated by the refractive power calculating circuit 72 and output to the superimposing circuit 75 is displayed on the TV monitor 76 with the symbols S, C, and A attached thereto, as shown in FIG. You. CCD camera 3
The image of the eye E based on the observation light of the eye E output from 4 is also displayed on the TV monitor 76 via the superimpose circuit 75. The superimposing circuit 75 also includes light receiving elements 60a to 60c, 61a to 61c, and 62a to 6 for the subject's eye presented by the element information presentation unit 74.
Information about the positions of 2c and 63a to 63c, specifically, an outline image of the light receiving element to be displayed on the TV monitor 76 is output, and this outline is also displayed on the TV monitor 76 in a superimposed manner. (In FIG. 6, the outer shape image of the light receiving element is shown using the reference numeral of each light receiving element).

Next, the refractive power measuring operation by the present apparatus will be described. First, the apparatus is turned on, a fixation image is projected on the eye E by the fixation optical system 2, and the TV monitor 76
, The alignment state of the present apparatus with respect to the subject's eye E is determined to be appropriate by the same procedure as that of the related art while referring to the image of the subject's eye E displayed on the screen. When the alignment state becomes appropriate, the center of the pupil of the image of the subject's eye E is displayed on the TV monitor 7.
6 are displayed so as to be substantially coincident with the upper, lower, left, and right center positions.

As shown in FIG. 6, the light receiving element 60a presented by the element information presentation section 74 is displayed on the TV monitor 76.
-60c, 61a-61c, 62a-62c and 63a
63c are displayed superimposed on the image of the eye E to be inspected. The light receiving elements 60a to 60c, 61a to 61c,
The outline images of 62a to 62c and 63a to 63c are arranged such that the vertical and horizontal center positions of these light receiving elements match the substantially vertical and horizontal center positions of the TV monitor 76.
4 is displayed so that the alignment state matches the pupil center position of the eye E at an appropriate time.

The examiner observes the state of the pupil and surface reflection of the eye E while watching the TV monitor 76, and selects a light receiving element to be used for measurement via the light receiving element changeover switch 70 according to the observation result. . For example, as shown in FIG. 5B, the pupil of the subject's eye is not sufficiently open, and the pupil diameter E1
When only the light receiving elements of the c-system are located inside the, and the other light-receiving elements are located above or outside the pupil diameter E1, the light-receiving elements of the c-system are selected. Or Figure 5
As shown in (c), the b-line and c-line are located inside the pupil diameter E1.
If the light receiving elements of the system are located and the other light receiving elements are located above the pupil diameter E1, the systems b and c
Select the light receiving element of the system. Even in the case where the pupil of the eye to be examined is not sufficiently opened in this way, by selecting only the light receiving element located inside the pupil, it is possible to receive only the measurement light which is not affected by shading of the iris. And accurate measurement can be performed.

Further, as shown in FIG. 5D, the range E3 of the reflected light reflected on the surface of the eye to be examined due to the influence of the intraocular lens and the like is large, and the light receiving element of the system a is located outside the range E3. If the other light receiving elements are located inside the range E3 of the reflected light, the light receiving element of the a system is selected.
Thus, even if the surface reflection of the eye to be examined is large,
By selecting only the light receiving element located outside the light receiving element, only the measuring light which is not affected by the surface reflection can be received, so that stable and accurate measurement can be performed. When the light receiving element is selected in this manner, the result of the selection is output to the element information presenting section 74 via the microprocessor 77, and the element information presenting section 74 superimposes the outline image obtained by inverting only the selected light receiving element. Output to the pause circuit 75. Therefore, only the selected light receiving element is highlighted on the TV monitor 76 to be distinguished from unselected light receiving elements. FIG. 6 shows a state where only the light receiving elements of the b-system are selected and highlighted.

After the selection of the light receiving element, the examiner presses a measurement start button (not shown) to start measuring the refractive power, and the refractive power calculating circuit 72 calculates the refractive power. Prior to the calculation by the refractive power calculation circuit 72,
The selection result of the light receiving element in the light receiving element changeover switch 70 is transmitted to the light receiving element switching circuit 7 through the microprocessor 77.
1 and only the output signal from the selected light receiving element is output from the light receiving element switching circuit 71 to the refractive power calculating circuit 72.
Output to.

The result of the selection of the light receiving element by the light receiving element changeover switch 70 is also output to the refractive power calculating circuit 72 via the microprocessor 77, and the refractive power calculating circuit 72 receives the light by the selected light receiving element. A conversion table indicating the correspondence between the phase difference of the measured measurement light and the refractive power of the subject's eye is called from the conversion table storage unit 73 and referenced,
The refractive power of the subject's eye is calculated based on the conversion table. This calculation result is output to the TV monitor 76 via the superimpose circuit 75, and displayed on the TV monitor 76.

It should be noted that the information presented by the element information presentation section 74 need not be the outer shape image of the light receiving element, but, for example, as shown in FIG. 7, the circumscribed circle J1 and inscribed circle J2 of the currently selected light receiving element. The image may be presented and displayed on the TV monitor 76. In addition, the information presented by the element information presentation unit 74 may be any information that can grasp predetermined information for selecting a light receiving element, such as the position of the currently selected light receiving element and the shape of the light receiving element. . Also, among the light receiving elements of the system a to the system c, an arbitrary light receiving element, for example, an intermediate light receiving element of the system b can be set as a default light receiving element, and measurement can be automatically started using the light receiving element of the system b. In addition, the light receiving element may be switched only when necessary.

Alternatively, instead of the examiner switching the light receiving elements, the light receiving elements may be automatically switched to the optimum light receiving elements. Therefore, in addition to the configuration described above, the pupil detection circuit serving as pupil detection means for detecting the position and shape of the pupil of the subject's eye, and the position and shape of the currently selected light receiving element are detected by the pupil detection circuit. A judgment circuit as judgment means for judging whether or not the pupil corresponds to the position and shape of the pupil; and if the judgment circuit judges that the pupil does not correspond to the pupil, the currently selected light receiving element is determined by the pupil detection circuit. A switching circuit may be provided as switching means for switching to a light receiving element having a position and shape corresponding to the detected position and shape of the pupil. Illustration of a pupil detection circuit, a judgment circuit, and a switching circuit is omitted.

The pupil detection circuit analyzes the image of the eye E to be displayed on the TV monitor 76, and determines the pupil of the eye E based on the difference between the luminance of the pupil of the eye E and the luminance of the pupils other than the pupil. A circuit similar to the conventional circuit for specifying the position and the pupil shape can be applied. Further, the determination circuit compares the position information of the light receiving element presented by the element information presentation unit 74 with the pupil position and the pupil shape of the eye E detected by the pupil detection circuit, and Determine whether the position and shape of the light receiving element that corresponds to the position and shape of the pupil detected by the pupil detection circuit, that is, whether or not all of the currently selected light receiving elements are located inside the pupil I do. The switching circuit controls the light receiving element changeover switch 70 based on the determination result of the determination circuit, and switches the light receiving element used for measurement. By adopting such a configuration, the examiner can save the trouble of switching the light receiving element,
In addition, it is possible to always accurately and quickly select an optimal light receiving element.

Alternatively, as shown in FIG. 12 as a conventional example, only one pair of light receiving elements is provided at the top, bottom, left and right to fix the light receiving element used for measurement, and a means for judging whether the light reception is properly performed is newly provided. And information indicating the reliability of the measurement result may be added according to the determination result. Therefore, while the optometry apparatus is basically configured in the same manner as the conventional one, the pupil detection circuit serving as pupil detection means for detecting the position and shape of the pupil of the eye to be examined, and the position and shape of the light receiving element are detected by the pupil detection circuit. A determination circuit as a determination means for determining whether or not the pupil corresponds to the position and shape of the pupil, when it is determined that the pupil does not correspond,
An information adding circuit as information adding means for adding predetermined information indicating the reliability of the refractive power to the refractive power calculated by the calculating circuit for calculating the refractive power of the eye to be examined may be provided. Illustration of the pupil detection circuit, the judgment circuit and the information addition circuit is omitted.

The pupil detection circuit detects the position and shape of the pupil of the subject's eye by analyzing the image of the subject's eye displayed on the TV monitor 76 in the same manner as described above. In addition, the determination circuit compares the position and shape of the light receiving element fixedly set in advance with the position and shape of the pupil detected by the pupil detection circuit, so that the position of the light receiving element is determined by the pupil detection circuit. It is determined whether the detected pupil corresponds to the position and shape of the pupil, that is, whether all the light receiving elements are located inside the pupil. If not all of the light receiving elements are located inside the pupil, it calculates how much the light receiving element protrudes from the inside of the pupil.

The information adding circuit adds information related to reliability, for example, information indicating the reliability in percent, to the refractive power calculated by the calculating circuit based on the result of the determination by the determining circuit. For example, if all the light receiving elements are determined to be located inside the pupil in the determination circuit, "1"
00% ", and when it is determined that a part of the light receiving element is located inside the pupil, information of a value less than 100% according to the area of the part is added. The information added in this manner is displayed on the TV monitor 76 together with the refractive power, and is referred to by the examiner.

In addition, various types of information regarding reliability may be adopted. For example, based on the position and shape of the light receiving element and the position and shape of the pupil, the calculated refractive power can be either valid or invalid. The information may be added to the information indicating whether the information is valid or invalid. When displaying the refractive power to which information of invalidity is added, a predetermined warning may be issued, or only the refractive power to which information of validity is added may be displayed.

Next, a second embodiment of the present invention will be described in detail with reference to the drawings. FIG. 2 is a side view showing the optical configuration of the apparatus according to the present embodiment, FIG. 8 is a front view of the stop of FIG. 2, FIG. 9 is a front view of the light receiver of FIG. 2, and FIG. It is an arrow B 'view. Configurations that are not particularly described are substantially the same as those of the first embodiment, and portions having the same functions are denoted by the same reference numerals. In the first embodiment, a plurality of light receiving elements are switched, whereas in the present embodiment, the measuring light is narrowed down to a predetermined range according to the measurement state by the plurality of apertures 40 to 42 without switching the light receiving elements.

As shown in FIG. 2, this apparatus has almost the same optical configuration as the apparatus in the first embodiment.
Second apertures 40 to 42 can be selectively arranged between 6 and the light receiver 18. Also, the light receiver 18 is shown in FIG.
As shown in the figure, the upper and lower light receiving elements 54 and 55 and the left and right pair of light receiving elements 56 and 57 are provided.

A pair of upper and lower light receiving elements 54 and 55 receive the measurement light scanned in the vertical direction, and a pair of left and right light receiving elements 5
Numerals 6 and 57 receive measurement light scanned in the left and right direction, and are basically the same as the conventional light receiving element shown in FIG. However, each of the light receiving elements 54 to 57 has a width W (in a direction away from the center position P of the optical axis) as compared with the light receiving element of FIG. 12 so as to be able to receive the measurement light projected through the apertures 40 to 42. Is widely formed.

The second diaphragms 40 to 42 are arranged so that the optical path of the measuring light between the diaphragm 16 and the light receiver 18 varies depending on the measurement state (the pupil of the eye E to be inspected, the degree of surface reflection of the eye E). It is selectively placed inside. As shown in FIGS. 8A and 8B, the apertures 40 to 42 are located at the center positions of the apertures 40 to 42.
A slit 43 is formed at a position and a shape common to each other, and the alignment light is projected onto the four-divided light receiving elements 50 to 53 of the light receiver 18 through the slit 43.

The apertures 40 to 42 have slits 40a to 40d and 41a to 41 of different shapes, respectively.
d, 42a to 42d are formed. Aperture 40
As shown in FIG. 8A, the distance L from the center position P of the optical axis
Slits 40a to 40d are formed at a distance from each other,
As shown in FIG. 8B, the slits 41a to 41a are separated from the center position P of the optical axis by a distance L2 (here, L2> L1).
As shown in FIG. 8C, the stop 42 has a distance L3 (where L3> L) from the center position P of the optical axis.
2) Slits 42a to 42d are formed at intervals.

Therefore, when the stop 40 is arranged in the optical path of the measurement light, only the measurement light in the range close to the center position P of the optical axis is smaller than when the other stops 41 and 42 are arranged. After passing through 40d, the light is projected onto the light receiving elements 54 to 57, and the measurement light in a range far from the center position P of the optical axis is blocked and not projected onto the light receiving elements 54 to 57. When the stop 42 is arranged in the optical path of the measurement light, the other stop 4
Compared to the case where 0 and 41 are arranged, only the measurement light in a range far from the center position P of the optical axis passes through the slits 42a to 42d and is projected on the light receiving elements 54 to 57, and is closer to the center position P of the optical axis. The measurement light in the range is blocked and the light receiving elements 54 to 57
Is not projected to The aperture 41 projects only the measurement light in the intermediate range between the apertures 40 and 42 to the light receiving elements 54 to 57.
FIG. 10 shows a state where the aperture 41 is arranged.

For example, when the pupil of the eye E is not sufficiently open, the stop 40 is disposed so that only the measurement light in a range close to the center position P of the optical axis is received by the light receiving element 54.
To 57 can be projected. Alternatively, when the surface reflection of the eye E is large, by disposing the stop 42, only the measurement light in a range far from the center position P of the optical axis can be projected on the light receiving elements 54 to 57. Therefore, measurement light in an unstable range can be shielded, and more accurate measurement can be performed.

The apertures 40 to 42 are arranged on a turret plate (not shown) serving as aperture switching means, and a selector switch (not shown) is operated by the examiner, and the turret plate is rotated according to the operation. Any one of the stops 40 to 42 is selectively disposed at a position substantially conjugate with the eye E in the optical path of the measurement light. Prior to this switching, similarly to the first embodiment, the image of the eye E to be inspected and the range of the measurement light projected via the apertures 40 to 42 are displayed on the TV monitor 76 in a superimposed manner, and the examiner can view the image. This is used as a reference when selecting one of the apertures 40 to 42. In addition, as described above, the optimal aperture for measurement may be automatically arranged using image analysis.

The measurement light converged through any of the diaphragms 40 to 42 is received by the light receiving elements 54 to 57, and an output signal is output from the light receiving elements 54 to 57 to the refractive power calculation circuit 72. Then, the refractive power calculation circuit 72 calculates the refractive power of the eye to be inspected based on the output signal input thereto, and the calculation of the refractive power is performed based on the shape of the stop arranged in the optical path. That is, in the present embodiment, a conversion table indicating the correspondence between the phase difference of the measurement light received by the light receiving element and the refractive power of the eye to be inspected is stored in the conversion table storage unit 73 for each shape of the diaphragm. Also, the refractive power calculation unit constantly monitors what shape of the apertures 40 to 42 are arranged in the optical path of the measurement light. Then, when calculating the refractive power, the refractive power calculation unit calls a conversion table corresponding to the shape of the stop currently arranged in the optical path of the measurement light from the conversion table storage unit 73, and uses the converted conversion table. Calculate the refractive power.

Next, a third embodiment of the present invention will be described in detail with reference to the drawings. FIG. 3 is a diagram showing an optical configuration of the present apparatus according to the present embodiment from the side, FIG. 11 is a view taken along the line CC ′ in FIG. 3 before disposing the variable power lens in the optical path, and FIG. FIG. 3 in a state where is disposed in the optical path.
FIG. Configurations that are not particularly described are substantially the same as those of the first embodiment, and portions having the same functions are denoted by the same reference numerals. In the first embodiment, a plurality of light receiving elements are switched, whereas in the present embodiment, the measuring light is changed to a predetermined size according to the measurement state by the plurality of variable power lenses 44 to 46 without switching the light receiving elements. Zoom.

As shown in FIG. 3, this apparatus has almost the same optical configuration as the apparatus in the first embodiment, but a plurality of variable power lenses 44 to 4 are provided between the lens 15 and the diaphragm 16.
6 are selectively arranged. Also, the light receiver 19 is shown in FIG.
As shown in FIGS. 1 and 12, in addition to the four-segment light receiving elements 50 to 53 configured in the same manner as in the related art, the light receiving elements 64 to 67 configured in the same manner as in the related art are provided. The light receiving elements 64 and 66 receive the measurement light scanned in the vertical direction, and the pair of left and right light receiving elements 65 and 67 receive the measurement light scanned in the left and right direction.

The plurality of variable power lenses 44 to 46 are selectively disposed between the lens 15 and the diaphragm 16 in accordance with the measurement state (the pupil of the eye E to be inspected, the surface reflection of the eye E). Each variable power lens focuses the measurement light on the light receiving surfaces of the light receiving elements 54 to 57 at different magnifications so that the light receiving surfaces of the light receiving elements 54 to 57 are completely covered with the measurement light ( The measurement light is scaled so that the measurement light irradiates all the light receiving surfaces of the light receiving elements 54 to 57). For example, as shown in FIG. 11, when the pupil of the eye E to be examined is not sufficiently open and the pupil diameter E1 is located on the light receiving elements 64 and 67, the plurality of variable power lenses 44 to 46 By arranging one of the lenses in the optical path of the measurement light, the measurement light is enlarged such that all of the light receiving elements 54 to 57 are located inside the pupil diameter E1, as shown in FIG. In this case, the light receiving element 19 is moved in the optical axis direction according to the variable power lens disposed. By selectively arranging the plurality of zoom lenses 44 to 46 in this manner, the measurement light can be constantly zoomed to an optimum size according to the position and shape of the light receiving element, and accurate measurement can be performed.

Such a plurality of variable power lenses 44 to 46
Is disposed on a turret plate (not shown) serving as a lens switching unit, and a selector switch (not shown) is operated by the examiner, and the turret plate is rotated according to the operation, so that an arbitrary magnification among a plurality of variable power lenses is obtained. Is selectively disposed at a position substantially conjugate with the eye E in the optical path of the measurement light. Prior to this switching, similarly to the first embodiment, the image of the eye E to be inspected and the range of the measurement light projected via the plurality of variable power lenses 44 to 46 are displayed on the TV monitor 76 in a superimposed manner. This is referred to when the examiner selects one of the plurality of variable power lenses 44 to 46. In addition, as described above, a variable power lens most suitable for measurement may be automatically arranged by using image analysis.

The measurement light converged through one of the plurality of variable power lenses 44 to 46 is received by the light receiving elements 54 to 57, and an output signal is output from the light receiving elements 54 to 57 to the refractive power calculation circuit 72. Is done. Then, the refractive power calculation circuit 72 calculates the refractive power of the eye to be examined based on the output signal input thereto, and the calculation of the refractive power is performed based on the magnification of the variable power lens disposed in the optical path. . That is, in the present embodiment, a conversion table indicating the correspondence between the phase difference of the measurement light received by the light receiving element and the refractive power of the eye to be examined is stored in the conversion table storage unit 73 for each magnification of the variable power lens. The refractive power calculation unit constantly monitors what magnification of the variable power lens is disposed in the optical path of the measurement light. When calculating the refractive power, the refractive power calculation unit stores a conversion table corresponding to the magnification of the variable power lens currently disposed in the optical path of the measurement light in the conversion table storage unit 73.
And calculates the refractive power using the called conversion table.

Although one embodiment of the present invention has been described, the present invention is not limited to the above-described embodiment, and may be embodied in various forms within the scope of the technical idea. Hereinafter, these different embodiments will be described. First, the optical system of the present apparatus is not limited to the configuration shown in FIGS. In the first embodiment, three pairs of light receiving elements are arranged vertically and horizontally, but three or more pairs of light receiving elements or two pairs of light receiving elements may be arranged. That is, it is sufficient that the plurality of light receiving elements are arranged along the direction away from the optical axis center of the measurement light. Further, the shape of each light receiving element is not limited to the illustrated shape, and any known shape may be adopted. For example, the size of the light receiving element near the center of the measuring light and the size of the light receiving element far from the center may be changed in accordance with the width or shape of the measuring light.

Also, the shape of the slit of the diaphragm according to the second embodiment is not limited to the one shown in the figure, and the slit near the center of the measurement light and the slit far from each other may be different from each other in accordance with the width and shape of the measurement light. Is also good. In the third embodiment, more variable power lenses may be selectively arranged.

[0066]

As described above, according to the first and second aspects of the present invention, a plurality of light receiving elements of the light receiving optical system are arranged along a direction away from the optical axis of the measurement light received by the light receiving element. A selection means for selecting a light receiving element to be used for measurement from among the light receiving elements of the above is used to perform measurement using only light receiving elements that are always located inside the pupil or light receiving elements that are not affected by surface reflection of the subject's eye. And the accuracy of the measurement can be greatly improved.

According to a third aspect of the present invention, there is provided a display means for displaying an eye to be inspected, and the display means displays predetermined information for selecting a light receiving element on the eye to be inspected in a superimposed manner. It is possible to easily know which position of the light receiving element is suitable for the measurement, and it becomes extremely easy to select the light receiving element.

According to a fourth aspect of the present invention, there is provided a pupil detecting means for detecting a position and a shape of a pupil of an eye to be examined.
Judgment means for judging whether or not the position and shape of the light receiving element currently selected by the selection means correspond to the position and shape of the pupil detected by the pupil detection means, and the judgment means does not correspond. Switching means for switching the currently selected light receiving element to a light receiving element having a position and shape corresponding to the position and shape of the pupil detected by the pupil detecting means, so that the optimum position is obtained. The arranged light receiving element is automatically selected, and accurate measurement can be performed more easily.

Further, according to the present invention, the pupil detecting means for detecting the position and shape of the pupil of the eye to be inspected, and the position and shape of the pupil whose position and shape of the light receiving element are detected by the pupil detecting means. Determining means for determining whether or not it corresponds to the shape; and adding predetermined information indicating the reliability of the refractive power to the refractive power calculated by the calculating means based on the determination result of the determining means. By providing the information adding means, information on the reliability of the refractive power is automatically added. By referring to this information, the reliability of the entire refractive power measurement can be improved.

Further, according to the present invention, a plurality of stops for narrowing the measuring light received by the light receiving element to different ranges according to the measurement state, and an arbitrary one of the plurality of stops are provided. By providing a diaphragm switching means for selectively arranging the diaphragm at a position substantially conjugate to the eye to be inspected between the light receiving element and the eye to be inspected, it is possible to project only the measurement light in a range suitable for measurement onto the light receiving element. It is possible to dramatically improve the accuracy of the measurement.

According to the present invention, a plurality of variable power lenses for changing the size of the measuring light so that the light receiving element is completely covered with the measuring light, and a plurality of variable power lenses are provided. Lens switching means for selectively arranging any variable power lens at a position substantially conjugate with the eye to be inspected between the light receiving element and the eye to be inspected, so that the measurement light has a size suitable for measurement. Can be projected onto the light receiving element, and the accuracy of the measurement can be dramatically improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an optical configuration of an objective refractive power measuring apparatus according to a first embodiment of the present invention, as viewed from a side.

FIG. 2 is a diagram illustrating an optical configuration of an objective refractive power measuring device according to a second embodiment, viewed from a side.

FIG. 3 is a diagram illustrating an optical configuration of an objective refractive power measuring device according to a third embodiment, as viewed from the side.

FIG. 4 is a block diagram showing an electrical configuration of the device shown in FIG.

5A is a view taken along the line AA ′ of FIG. 1, wherein FIG. 5A is a view showing the entire light receiver, FIG. 5B is a view showing a light receiver selected when the pupil diameter is extremely narrow, and FIG. () Is a diagram showing a light receiver selected when the pupil diameter is slightly narrow, and (d) is a diagram showing a light receiver selected when the range of the reflected light of the eye to be examined is wide.

FIG. 6 is a diagram showing a display screen of a TV monitor.

FIG. 7 is a diagram showing a display screen of a TV monitor.

FIG. 8 is a front view of the stop shown in FIG.
, (B) is a front view of the diaphragm 41, (c) is a diaphragm 4
2 is a front view of FIG.

FIG. 9 is a front view of the light receiver of FIG. 2;

FIG. 10 is a view taken in the direction of arrows B-B 'in FIG.

FIG. 11 is a view C of FIG. 3 before a variable power lens is arranged in an optical path;
FIG.

FIG. 12 is a view taken along the line CC ′ in FIG. 3 in a state where the variable power lens is arranged in the optical path.

FIG. 13 is a front view of a light receiver of a conventional objective refractive power measuring device.

FIG. 14 is a front view of a light receiver of a conventional objective refractive power measuring device.

FIG. 15 is a front view of a light receiver of a conventional objective refractive power measuring device.

[Explanation of symbols]

 E Eye to be inspected E1 Position corresponding to the inner diameter of the iris of the eye to be inspected E2 Position corresponding to the outer diameter of the iris of the eye to be inspected E3 Range of the reflected light reflected by the cornea of the eye to be inspected J1 Circumscribed circle of the light receiving element J2 Inscribed circle P Center position 1 Measurement optical system 2 Fixation optical system 3 Observation optical system 11, 31 Infrared light source 12, 15, 23, 33 Lens 13 Chopper 14, 24 Half mirror 16, 40-42 Aperture 17 Light receiver 21 Visible light source 22 Fixation target 32 Total reflection mirror 34 CCD camera 40-42 Aperture 43 Slit 44-46 Magnifying lens 50-53 Quadrant light receiving element 60-63, 54-57, Light receiving element 70 Light receiving element changeover switch 71 Light receiving element Switching circuit 72 Refractive power calculation circuit 73 Conversion table storage unit 74 Element information presentation unit 75 Superimpose circuit 76 TV monitor 77 M Black processor

Claims (9)

[Claims] A projection optical system for projecting measurement light onto a fundus of an eye to be inspected; a light receiving optical system for receiving, via a light receiving element, measurement light projected by the projection optical system and reflected by the eye to be inspected; Calculating means for calculating the refractive power of the eye to be inspected based on the measurement light received by the light receiving optical system, wherein the light receiving element receives the light receiving element of the light receiving optical system. A plurality of light receiving elements arranged along a direction away from the optical axis of the measuring light to be measured, and a selecting means for selecting a light receiving element to be used for measurement from the plurality of light receiving elements. 2. The objective refraction according to claim 1, wherein said calculating means calculates the refractive power of the eye to be inspected based on predetermined information on the light receiving element selected by said selecting means. Force measuring device. 3. The display device according to claim 1, further comprising: display means for displaying the eye to be inspected, wherein the display means displays predetermined information for selecting the light receiving element so as to overlap the eye to be inspected. An objective refraction measuring device according to item 1. 4. A pupil detecting means for detecting a position and a shape of a pupil of an eye to be examined, and a position and a shape of a pupil whose position and shape of a light receiving element currently selected by said selecting means are detected by said pupil detecting means. Judging means for judging whether or not it corresponds to the shape; and when the judging means judges that it does not correspond, the position of the pupil detected by the pupil detecting means with the currently selected light receiving element. 4. The objective refractive power measuring apparatus according to claim 1, further comprising: a switching unit configured to switch to a light receiving element having a position and a shape corresponding to the shape and the shape. 5. A projection optical system for projecting measurement light onto the fundus of an eye to be inspected, a light receiving optical system for receiving, via a light receiving element, measurement light projected by the projection optical system and reflected by the eye to be inspected, Calculating means for calculating the refractive power of the eye to be inspected based on the measurement light received by the light receiving optical system, wherein the pupil detection for detecting the position and shape of the pupil of the eye to be inspected Means, determining means for determining whether the position and shape of the light receiving element correspond to the position and shape of the pupil detected by the pupil detecting means, and based on the determination result of the determining means, An objective refracting power measuring device, comprising: information adding means for adding predetermined information indicating the reliability of the refractive power to the refractive power calculated by the calculating means. 6. A projection optical system for projecting measurement light onto the fundus of an eye to be inspected, a light receiving optical system for receiving, via a light receiving element, measurement light projected by the projection optical system and reflected by the eye to be inspected, Calculating means for calculating the refractive power of the eye to be inspected based on the measuring light received by the light receiving optical system, wherein the measuring light received by the light receiving element is measured. A plurality of apertures for narrowing down to different ranges according to the following; and an aperture for selectively arranging an arbitrary aperture among the plurality of apertures at a position substantially conjugate with the eye to be inspected between the light receiving element and the eye to be inspected. And a switching unit. 7. An objective refractive power measuring apparatus according to claim 6, wherein said calculating means calculates the refractive power of the eye to be inspected based on a stop arranged by said stop switching means. 8. A projection optical system for projecting measurement light onto the fundus of the eye to be inspected, a light receiving optical system for receiving, via a light receiving element, measurement light projected by the projection optical system and reflected by the eye to be inspected, Calculating means for calculating the refractive power of the eye to be inspected based on the measurement light received by the light receiving optical system, wherein the light receiving element is completely covered with the measurement light. A plurality of variable power lenses for changing the magnification of the measurement light, and any one of the plurality of variable power lenses is substantially conjugate with the subject's eye between the light receiving element and the subject's eye. And a lens switching means selectively disposed at a position. 9. The objective refractive power measurement according to claim 8, wherein said calculating means calculates the refractive power of the eye to be inspected based on the variable power lens arranged by said lens switching means. apparatus.